Analysis of iodine nutritional status among children and pregnant women before and after adjusting iodine content in iodine salt in Xinjiang Production and Construction Corps

Objective To analyze the impact of reduction of iodine content in iodine salt on iodine nutrition level among children and pregnant women in Xinjiang Production and Construction Corps (hereinafter referred to as the Corps). Methods In 2011 (before adjusting), the population proportional probability sampling (PPS) method was used to select 30 round fields in the Corps, one primary school was selected in each round field, and 40 children aged 8 - 10 years old (half males and half females) were taken from each primary school, to collect salt samples from their homes, salt iodine level was determined and thyroid examination was performed; among those 40 children, 12 children (half males and half females) were selected, and urine samples were collected to test urine iodine level; at the same time, 10 pregnant women were selected from the school location, and their urine samples were collected to test urine iodine level. In 2015 (after adjusting), in 14 divisions of the Corps, one round field was selected in each division from each of five directions of east, west, south, north and middle. Four company teams were selected in each round field, and 15 salt samples of households were collected in each company team, salt iodine was detected. One team primary school was selected in each round field, 40 children aged 8 - 10 years old (half males and half females) were taken from each primary school, urine samples were collected to detect urine iodine level, and thyroid examination was performed; 20 pregnant women were taken from each round field, and urine samples were collected to detect urine iodine level. A comparative analysis of iodine nutritional status in children and pregnant women in 2011 and 2015 was conducted. Goiter was examined by B-ultrasonography; salt iodine was detected by direct titration; urine iodine was detected by arsenic cerium catalytic spectrophotometry (WS/T 107-2006). Results A total of 1 195 and 4 215 salt samples were collected in 2011 and 2015, the medians of salt iodine were 32.3 and 28.2 mg/kg, respectively; the goiter rates of children were 3.4% (42/1 220) and 1.0% (26/2 552), respectively, both were below national standards (5.0%); the medians of urine iodine of children were 235.3 and 217.9 μg/L, respectively, both were more than the appropriate level; the medians of urine iodine of pregnant women were 183.0 and 157.7 μg/L, respectively, both were at appropriate level. Conclusion The reduction of salt iodization has no significant effect on iodine nutritional status in children and pregnant women, the iodine nutrition levels of children and pregnant women are good. Key words: Iodine; Salts; Urine; Goiter; Child; Pregnant women